Experimental study and theoretical analysis on the flexural behavior of glulam bolted joints with prestressed steel strips

The glulam bolted joint with prestressed steel strips was proposed and investigated systematically. Experimental study was conducted considering the variation of pre-strain of steel strips. The presence of prestressed steel strips led to a delay in the onset and propagation of cracking with a pronounced increase in bearing capacity compared with ordinary glulam bolted joints, i.e. by 41.15%, 52.01% and 53.33%, respectively, and significantly higher deformation capacity, with the ductility increasing by 15.38%, 88.11% and 104.90% respectively. A three-dimensional finite element analysis considering mixed-mode cohesive zone modeling was performed and verified to be effective to reproduce crack path observed in the experiments. Moreover, a quasi-non-linear fracture mechanics model based on a Timoshenko beam on elastic foundation theory was extended in order to take into account the influence of the prestressed steel strips on the ultimate bearing capacity. Analytical results demonstrated how ultimate bearing capacity changed with pre-strain, thickness, width and spacing of strips and a series of design recommendations were supplied.